I'm going to be making a new backpack for myself, having worn out my old one. I'm curious if anyone has used a pack with uncoated fabric before. It seems to me that the PU coating on pack fabric is not very water proof and it wears off after a while anyway. I'll be keeping my stuff in waterproof stuffsacks so I don't see the need to use the heavier, coated material. I also think the pack could potentially dry out faster if it's not coated because the inside stays wet in my experience. However, I'm hesitant to use uncoated fabric because every pack uses coated nylon and it just seems like maybe I'm missing something. Thoughts?

I've been using uncoated fabric on all my myog backpacks for well over 10 years. I love it. It has all the advantages you mention plus I can throw the bag in the washer. I really like this because I'm a heavy sweater and my packs can get pretty smelly.

I, my wife and a friend have all used 1.9 ounce uncoated ripstop on our myog backpacks without any problems. I am currently testing a a bag made of 1.1 ounce uncoated ripstop. No problems so far.

One reason everyone uses a coated pack fabric is it is actually VERY hard to find an uncoated fabric. The common acrylic coating is used just to bond the threads together rather than for water-proofing. It stops terrible fraying at the edges too.

I also still have a couple of rolls of uncoated 1.9 ounce ripstop that I bought in the 1970s for almost nothing. I use it for first drafts. It is a very ugly color (baby crap yellow?). I bought the black fabric to please my wife and I use it for the final drafts.

Forty year old uncoated ripstop on rolls, stored inside a house, away from the sun looks and wears just like new. Not so for the coated nylon. Some of that has morphed into sticky, smelly mess.

I'm working on a pack right now that uses uncoated fabric. The bottom is reinforced with about 4oz nylon, but most of the pack body is uncoated 1.8oz dacron. It should absorb less water and dry faster than nylon, I think. I don't know how the choice to use dacron over nylon will turn out, but I always use a packliner and I don't expect to regret choosing uncoated fabric.